1. Field of the Invention
The present invention relates generally to the field of high-speed data transfer, and more specifically to enabling fast restoration of failed connections and flexible control over the restoration process in a data transfer architecture.
2. Description of the Related Art
High-speed high bandwidth data communication systems employ a variety of components to facilitate the receipt and transmission of data packets. Components include network nodes, which may be comprised of functional components such as framers and cross- The cross connect allows portions of a digital bit stream to be rerouted or connected to different bit streams. Cross connects enable data traffic to be moved from one ring to the next ring in a path and ultimately to the destination node.
Typically, these high-speed high bandwidth data communication systems are realized by interconnecting a large number of network nodes to receive and transmit ever-increasing amounts of data. A network node within these systems may be comprised of a variety of functional components, and in certain circumstances may encounter “connection faults,” or faults in establishing connections between network nodes. A network node that remedies connection faults by switching to redundant connections may have health detection functionality and restoration functionality executing in separate network elements, or in other words, one component may assess health while another component may address health. Each network element is responsible for measuring and monitoring the health or quality of all available transport channels, whether carrying traffic or in standby available for provisioning.
To monitor transport channel health and address failures, components maintain or exhibit certain parameters called “health codes.” These elements may include a health detecting function that can generate a suite of health codes in the form of statuses, alarms and defects related to the quality of each channel. Certain elements may communicate their health codes to other downstream elements in the system.
Transport networks can rapidly restore connections upon failures. For example, SONET/SDH employs various restoration schemes, including but not limited to Bi-directional Line Switched Ring (BLSR)/Multiplex Section Shared Protection Ring (MSSPring), Unidirectional Path Switched Rings (UPSR)/Subnetwork Connection Protection Rings (SNCP), Line protection Automatic Protection Switching Linear 1+1 (APS 1+1), Mesh protection, and Complex mesh schemes (e.g. Meta−Mesh (M−M), Shared Backup Path Protection (SBPP), and True Path Restoration).
These various restoration schemes may involve activities at the framer device, any cross-connection matrices connected to them, and a controller to re-provision the matrices for the new connections, where cross connect matrices are provided for traffic routing and map inputs to outputs for the cross connections.
Today's high speed communication systems, such as those conforming to SONET/SDH, generally support standard techniques to detect and filter defects and alarms and communicate the detected status to a repairing element, typically a cross connect. The inherent difficulty with these deployed SONET/SDH systems is that they typically employ fixed and generally inflexible hardware circuits to determine the repair needed and effectuate the repair at the cross connect. Current hardware solutions can frequently restore the failed connection, but these hardware solutions may not provide scheduling and health analysis functions, and frequently are not able to modify stored connection maps, where connection maps provide a listing of current connections for the component. Due to these limitations, hardware solutions require storage of multiple pre-provisioned connection maps, and storage requirements can limit the number of restoration schemes and connection maps available. Also, stored fixed restoration schemes employing pre-provisioned connection maps to implement repairs are not well suited to effectively restore multiple simultaneous channel failures. Operator commands, time of day, or certain node and network conditions can trigger traffic rerouting and require replacing the current primary map with one of the alternate maps.
Health codes may be exported to an external Network Management System/Element Management System (NMS/EMS) that executes system software to determine the appropriate repair. Once an element or node makes a decision to restore/repair, the NMS/EMS communicates commands to the repairing element to implement the repair. NMS/EMS based solutions are unable to restore failed connections in a relatively rapid manner, partially due to communications and processing overhead supporting alarms and defects from the detecting element. SONET/SDH standards define relatively fast switching times objectives (e.g. less than 50-millisecond protection switching) for various automated protection schemes (e.g. 1+1 and 1:N line protection) to rapidly restore connections after failure.
Thus, the common challenge faced in today's network architectures occurs when the network element responsible for repairing the a failure within a transport channel must rapidly and accurately interpret the transport channel health and initiate appropriate corrective restoration scheme to restore one or more simultaneous failing connections.
A design that enables efficient analysis of transport channel health and incorporates flexible user control to reconfigure the behavior of the decision making process at the cross-connect matrix in response to detected failures, and provides rapid restoration of failed connections may provide increased throughput and other advantageous qualities over previously known designs, including designs employing the SONET/SDH architecture.